Hydrotreating catalyst

ABSTRACT

1. A PROCESS OF PREPARING A CATALYST OR CATALYST SUPPORT WHICH COMPRISES MIXING PREFORMED ALUMINA PARTICLES WITH SILICA SOL IN AN AMOUNT SUFFICUENT TO FOEM A SURFACE COATING OF SIO2 ON SAID ALUMINA WHICH COATING AFTER DRYING AND CALCINING CONSTITUTES LESS THAN 2.5% SIO2, BASED ON THE WEIGHT OF A12O3 BUT IS SUFFICIENT TO ENHANCE THE HYDROTREATING ACTIVITY OF SAID CATALYST, AND CONTACTING SAID ALUMINA PARTICLES BEFORE, DURING OR AFTER SAID MIXING WITH AN ACTIVATING AGENT IN THE FORM OF A COMPOUND EFFECTIVE TO MAKE THE ALUMINA MORE REACTIVE WITH THE SILICA OF SAID SILICA SOL EITHER BY CONVERTING A PORTION OF THE ALUMINA TO A WATER SOLUBLE STATE OR BY COATING THE ALUMINA WITH A WATER SOLUBLE ALUMINUM COMPOUND, SAID ACTIVATING AGENT BEING SELECTED FROM THE GROUP CONSISTING OF ACETIC ACID, FORMIC ACID, ALUMINIUM ISOPROPOXIDE, CHLOROHYDROL AND TETRAMETHYLAMMONIUM HYDROXIDE.

United States Patent 3,840,477 HYDROTREATING CATALYST David G. Braithwaite, Brookhaven, Miss., and Carl F. Cross and Michael R. Basila, Munster, Ind., assignors to Nalco Chemical Company, Chicago, Ill. No Drawing. Filed Aug. 3, 1972, Ser. No. 277,733 Int. 'Cl. B01j 11/40 U.S. Cl. 252-455 R 14 Claims ABSTRACT OF THE DISCLOSURE An improved catalyst support and improved results in hydrotreating are obtained by preparing a catalyst comprising alumina surface treated with a very small amount of silica interacted with the alumina.

BACKGROUND Alumina catalysts useful in a variety of fixed bed hydrotreating operations, e.g., hydrocrac-king, desulfurization, hydrodenitrogenization and hydrogenation are Well known.

Prior art alumina support materials have generally been prepared in the form of extrudates or pellets. Certain types of beaded or spherical alumina catalysts have also been proposed.

The art of making catalysts is highly developed and over the years many improvements have been effected resulting in catalysts of a relatively high degree of sophistication and catalytic activity. In spite of the advanced state of the art, it would be highly desirable to industry to have available hydrotreating catalysts of increased activities, so that a given amount of catalyst will produce an ever-increasing amount of product and thus increase the productivity and improve the economics of the various hydrotreating operations.

OBJECTS One of the objects of the present invention is to provide a catalyst having an improved activity per unit amount of catalyst.

DETAILED DESCRIPTION OF THE INVENTION In practicing the invention it is desirable to effect interaction of the alumina with the silica by contacting -the alumina in the form of an extrudate, spheres or beads 5 with a chemical reagent which tends to solubilize the alumina at its surface so that the possibility of interaction between the alumina and the silica is enhanced. To accomplish this, the alumina beads or spheres or extrudate either before, during or after the addition of silica as a silica sol or sodium silicate are brought into contact with an activating agent which is effective to make the alumina more reactive with silica, either by converting a portion of the alumina to a water soluble state or by adding a water soluble alumina compound. It will be understood,

therefore, that the term activating agen as used herein is intended to include and cover various types of substances which will function for the aforesaid purpose. Thus, it has been found that organic acids such as acetic acid and formic acid which form water soluble aluminum salts can be employed for this purpose. A strong organic base such as, for example, tetramethylammonium hydroxide can also be used. Another substance which can be employed as an activating agent is chlorohydrol which is a 50% by weight solution of hydrolyzed aluminum chloride containing aluminum hydroxide and aluminum millimicrons and the surface area from 50 to 700 m./ g.

The sol can vary widely in \SiO' concentration, e.g., from 1 to 50% by weight as SiO Typical aqueous colloidal silica sols useful in preparing the catalysts of the invention are set forth below in 40 Table I:

TABLE I D 10. 2 3. 1 8. 6 9. 0 8. 5 10.0 10.0 Average particle size, millimicrons 11-16 16-22 16-22 17-25 40-60 8 15 Average surface area, mfi/gram..- 190-270 135-190 135-190 120-176 50-75 375 200 Specific gravity at 68 F..- 1. 205 1. 230 1. 255 1. 385 1. 390 1. 214 1. 296 Viscosity at 77 F., cps.-. 5 5 5 70 5-10 7 8 N820, percent 0. 4 0. 01 0. 10 0. 30 0.10 0.65 0. 40

Another object of the invention is to provide a new and improved method of producing a catalyst of the type described.

Still a further object of the invention is to provide new and useful results in hydrotreating operations. Other objects will appear hereinafter.

BRIEF SUMMARY OF THE INVENTION In accordance with the invention it has been found that an improved catalyst and catalyst support for use in hydrotreating can be obtained by coating alumina, e.g., extrudates, beads or spheres, usually having a dimension from about 0.01 inch to about 0.50 inch, with a small amount of silica, the amount of silica, as SiO in the resultant catalyst, after drying and calcining, being sufficient to enhance the activity of the alumina in hydrotreating but usually less than 2.5% by weight of the alumina, as A1 0 usually within the range of about 0.2% to 1.2% by weight. The catalyst is preferably prepared under conditions adapted to produce interaction between the silica and the alumina, as hereafter described.

In the silica sols given in Table I the liquid carrier for the SiO particles is water but the sol can also be one in which at least a portion of the water is replaced by a 5 water miscible alcohol or glycol. For example, Nalcoag 1129 can be used which is an acid sol generally similar to Nalcoag 1034A except that a part of the Water is replaced with isopropanol so that instead of water as a liquid carrier for the SiO the sol contains 40% to 50% isopropanol.

Since the amount of silica being added to the alumina in the form of a sol is extremely small, it is usually necessary to provide additional liquid carrier in the form of water or an aqueous solution of the activating agent in order to coat the alumina spheres.

agent is mixed with the silica sol and the mixture is added to the alumina which is in the form of beads or spheres or an extrudate. The coated alumina particles are then dried and finally calcined. The drying step is preferably done at a temperature of at least 180 C. for one hour. Longer drying times and higher or lower temperatures can 'be used. For example, the drying step might be conducted at temperatures of 30 C. to 180 C. with a longer drying time being required at the lower temperatures and a shorter drying time at the higher temperatures. The drying step removes enough moisture so that on subsequent calcining the evolution of water does not become too violent.

Calcining should be at temperatures in excess of 480 C. (ca. 900 F.) and preferably above 538 (ca. 1000 F.). A temperature of 594 C. (ca. 1100 F.) achieves good results.

Where the activating agent is acidic, it is desirable to use an acidic silica sol. It is also desirable that the finished catalyst contain a low amount of sodium. Silica sols such as Nalcoag 1129 and Nalcoag 1034A are preferred for the practice of the invention.

The amount of water or other Water miscible carrier used with the silica particles should be sufficient so that the alumina particles are thoroughly wet. In any event, however, the amount of silica is less than 2.5% by weight of the alumina.

The mixing of the alumina shaped particles with the silica sol and activating agent should be such as to insure intimate contact and coating of the alumina.

In order to evaluate the invention silica coated alumina spheres and alumina extrudates were subjected to a standard testing method in a hydrotreating process wherein the volume activity and weight activity of the catalyst of the invention were compared respectively with the volume activity and weight activity of a standard catalyst. The

ratios of the respective activities then give a basis for determining the amount of enhanced activity. In the following examples it will be understood that the volume activities and the weight activities are ratios of the activity of the catalyst tested to a standard catalyst having an activity of 1.0.

The invention will be further illustrated but is not limited by the following examples in which the quantities are stated in parts by Weight unless otherwise indicated.

EXAMPLE I 500 grams of alumina spheres of approximately Vs diameter were mixed with 5 ml. of Nalcoag 1034A and then with 500 grams and 50% acetic acid. The mixture was dried and then calcined at 1100 F. for 2 hours.

EXAMPLE II 5 ml. of Nalcoag 1034A was mixed with 500 grams of a 25% aqueous solution of tetramethylammonium hydroxide and'the resultant mixture was then mixed with 500 grams of A3 diameter alumina spheres and allowed to air dry. The resultant product was then dried at 180 C. for one hour and finally calcined at 1100 F. for 2 hours.

EXAMPLE III 500 grams of a 14% aluminum isopropoxide solution in ethyl Cellosolve was prepared by boiling the alumnum propoxide in the ethyl Cellosolve with the elimination of isopropyl alcohol. 1.7 grams of Nalcoag 1129 was added to this solution and the resultant mixture was then mixed with 500 grams of /s" diameter alumina spheres. Thereafter the coated alumina spheres were dried at 180 C. for 2 hours and finally calcined at 1100" for 2 hours.

EXAMPLE IV The procedure was the same as in Example I except that 8 grams of 50% aqueous solution of gluconic acid was added to the mixture, the gluconic acid being added in this case as a stabilizing agent.

4 EXAMPLE v 14 grams of Nalcoag 1034A were mixed with 200 grams of a 50% aqueous solution of chlorohydrol and 300 grams of water. At this point a clear, slightly opalescent solution resulted. This was mixed with 500 grams of 4;" diameter alumina spheres. As these dried, the coated spheres became very sticky and formed clumps. After drying at 180 C. for one hour and calcining at 1100 F. for 2 hours, all tendencies to stick together disappeared.

EXAMPLE VI 20 grams of Nalcoag 1034A were mixed with 50 grams of formic acid and 450 grams of water. This mixture was then mixed with 500 grams of alumina spheres averaging /a" in diameter and allowed to air dry overnight. The coated spheres were then dried at 180 C. for 2 hours and calcined at 1100 F. for 2 hours.

EXAMPLE VII 52 grams of silica acid sol (7% by weight SiO Were mixed with 1500 grams of water. The diluted sol was then mixed with 600 grams of alumina spheres. The temperature of this mixture was raised to 180 F. and held at 180i2F. for one hour. The liquid was drained from the spheres. The spheres were dried at 300 F. for two hours and calcined at 1000 F. for two hours.

EXAMPLE VIII 70 grams of sodium silicate solution (28.5% SiO by weight) were mixed with 12.0 grams of sodium hydroxide pellets and 5000 grams of water. To this solution, 2040 grams of dry alumina powder were added. The temperature of this mixture was raised to 180 F. and held at 180-32 F. for one hour with constant stirring. The liquid was removed by filtration, and 5000 ml. of water were passed through the resulting filter cake to remove any residual sodium hydroxide or sodium silicate. The material was oven dried, after which a small amount of water was added to adjust the moisture of the material to a level suitable for extrusion. The alumina was extruded into cylindrical particles about /s" long and V thick. The resulting formed alumina was calcined in air at 1000 F. for two hours.

EXAMPLE IX 246 grams of silica acid sol (7.0% SiO by weight) were mixed with 5000 grams of water. The quantity of 2040 grams of dry alumina powder was added to this solution. The temperature of this mixture was raised to 180 F. and held at li2 F. for one hour with constant stirring. The liquid was removed by filtration and 5000 ml. of water were passed through the resulting filter cake to remove any residual unreacted silica. The material was oven dried. The material was extruded after adding a suitable amount of water. The extruded alumina was calcined in air at 1000 F. for two hours.

EXAMPLE X 8 grams of sodium silicate were mixed with 1.5 grams of sodium hydroxide pellets and 5 00 .grams of water. This solution was then mixed with 227 grams of alumina pellets. The mixture was allowed to stand for one hour. The liquid was decanted and the pellets were then dried at 300 F. for two hours and calcined at 1000 F. for an additional two hours.

EXAMPLE XI 28 grams of silica acid sol (7% by weight SiO were mixed with 500 grams of Water. The diluted sol was then mixed with 227 grams of alumina pellets. The mixture was allowed to stand for one hour after which the liquid was drained off. The pellets were dried at 300 F. for two hours and calcined at 1000 F for two hours.

Hydrodesulfurization catalysts were prepared by impregnating each of the catalyst supports in the foregoing examples with cobalt and molybdenum by conventional methods, thereafter drying the catalyst at 300 F.- for two hours and finally calcining at 1100 F. for two hours.

treating activity of said catalyst, and contacting said alumina particles before, during or after said mixing with an activating agent in the form of a compound eifective to make the alumina more reactive with the silica of said silica sol either by converting a portion of the alumina Evaluation data is given in Table II in which SA is surface 5 to a water soluble state or by coating the alumina with a area in square meters per gram and PV is pore value in 'water soluble aluminum compound, said activating agent cc. per gram. The last column gives the comparative data being selected from the group consisting of acetic acid, for a standard catalyst where there was no silication of formic acid, aluminum isopropoxide, chlorohydrol andthe alumina catalyst support. tetramethylammonium hydroxide.

TABLE II Standard catalyst, Example I 11 III IV V VI VII VIII IX X XI silleatign M003" 12.2 13.0 13.1 13.6 13.2 13.0 13.3 12.5 12.7 11.2 10.8 11.3 000... 3.6 3.5 3.5 3.6 2.8 3.5 3.5 3.3 3.0 2.6 2.9 2.8 8101... .7 .75 .2 .8 .3 2.0 .7 .9 .7 .8 1.0 0 A120; 83.0 83.0 83.0 82.0 84.0 81.0 82.0 82.0 83.0 85.0 84.0 85.0 Percent 810; to A1103 84 90 24 .98 36 2. 47 85 1. 1 84 94 1. 2 0 SA 210 220 205 170 210 195 240 190 205 180 180 180 PV1200,A. .60 .56 .67 .67 .68 .68 .66 .53 .48 .47 .46 .47 PV 100A." .20 .21 .18 .21 .18 .26 .22 .25 .21 .22 18 Apparent bulk density (g./1n1.) .53 60 .54 .53 .53 .53 .54 .72 .72 .74 .75 .7 VoLactivity 1.3 1.3 1.3 1.3 1.2 1.1 1.2 1.6 1.3 1.2 1.1 1,0 Wt. activity 1.2 1.1 1.2 1.2 1.1 1.0 1.1 1.6 1.3 1.3 1.2 1.0

'PV less than 1,200 A. "PV less than 100 A.

In the foregoing examples, the alumina consists essen- 2. A process as claimed in claim 1 in which said tially of pure alumina (A1 0 Compositions which are alumina particles have a diameter of from about 0.01 inch useful and procedures for preparing the beads or spheres to about 0.50 inch. include materials and processes described in one or more 3. A process as claimed in claim 1 in which said aluof US. Pats. 2,996,460, 2,988,520, and 3,520,654. It mina particles are in spherical form. should be understood that the invention is not limited to 4. A process as claimed in claim 1 in which said aluany particular method of preparing the beads or spheres mina particles are extrudates. or trudate 5. A process as claimed in claim 1 in which said activat- The silica coated alumina particles prepared as deing agent is acetic acid. scribed herein can be used as such in hydrotreating proc- 6. A process as claimed in claim 1 in which said activatesses or they can be used as catalyst supports for catalytiing agent is formic acid. cally active metals, including one or more of the follow- 7. A process as claimed in claim 1 in which said acti- 40 vating agent is tetramethylammonium hydroxide.

Ni Sn 8. A process as claimed in claim 1 in which said ac- C w tivatlng agentns an aluminum lsopropoxlde solution ob- Fe g tamed by boilmg aluminum 1sopropox1de in ethylene glycol monoethylether with the elimination of isopropyl al- 8 fi cohol. OS process as claimed in claim 1 in which said added Cu Pt act1vat1ng agent 1s chlorohydrol. Zn Pb 10. A process as cla 1rned 11 1 cla1m 1 in which said silica Mo Bi sol 1s apphed as an acldlc silica sol. Pd Rare earths A ydrotreatmg catalyst or catalyst support ob- Cd tamed accordmg to the process claimed in claim 1.

12. A hydrotreating catalyst comprising a catalyst sup For instance, as previously described, ahydrodesnlfunzaport as claimed in claim 1 and a catalytically active tioll Catalyst is made y depositing cobalt and molybde' metal other than aluminu-ml, said catalytically active metal B11111 p the catalyst PP being selected from the group consisting of Ni, Co, Fe,

The term hydrotreating refers to a reaction where1n Mn Cr, v c Zn Mo Pd, Sn, W, Mg, Re, Os Pt, mixtures of hydrocarbons are contacted with a catalyst in Pb Bi, and rare earths the presence of added hydrogen at elevated temperatures A hydrotreating catalyst as claimed in claim 12 and pressures- I11 hydrocfacking, Which is one form of wherein said catalytically active metal comprises cobalt hydrotreating, higher boiling hydrocarbons are converted and m01yhdehum to lower boiling products. It desulfurization, the purpose 14 A process as claimed in claim 1 in Which the s o of the hydrotreating process is to remove sulfur from the is 0 to 12% by Weight f the alumina hydrocarbons. In hydrodenitrogenization the purpose of the hydrotreating process is to rgmdcl ve nitroge1111 com- References Cit d pounds from the hydrocarbons. In y ogenation t e purpose of the hydrotreating process is to add hydrogen to UNITED STATES PATENTS the chemical structure of the hydrocarbons or to cause :1 2,216,262 10/1940 B1001} t a1. 252-451 rearrangement of the chemical structure by the addi- 2,852,473 9/ 1958 F P 252-451 tion f hydrogen 3,650,989 3/1972 Hmdln et al 252451 The invention is hereby claimed as follows: 3,598,759 8/1971 Bertolacini 252-455 R 1. A process of preparing a catalyst or catalyst support 3,560,370 2/ 1971 Billon et al. 252-455 R which comprises mixing preformed alumina particles with 3,657,153 4/ 1972 Bucur et a1. 252455 R silica sol in an amount suflicient to form a surface coating 3,662,002 5/1972 Magerlein et al. 252455 R of S10 on said alumina which coating after drying and calcining constitutes less than 2.5% SiO based on the CARL F. DEES, Primary Examiner weight of A1 0 but is sufiicient to enhance the hydro- 

1. A PROCESS OF PREPARING A CATALYST OR CATALYST SUPPORT WHICH COMPRISES MIXING PREFORMED ALUMINA PARTICLES WITH SILICA SOL IN AN AMOUNT SUFFICUENT TO FOEM A SURFACE COATING OF SIO2 ON SAID ALUMINA WHICH COATING AFTER DRYING AND CALCINING CONSTITUTES LESS THAN 2.5% SIO2, BASED ON THE WEIGHT OF A12O3 BUT IS SUFFICIENT TO ENHANCE THE HYDROTREATING ACTIVITY OF SAID CATALYST, AND CONTACTING SAID ALUMINA PARTICLES BEFORE, DURING OR AFTER SAID MIXING WITH AN ACTIVATING AGENT IN THE FORM OF A COMPOUND EFFECTIVE TO MAKE THE ALUMINA MORE REACTIVE WITH THE SILICA OF SAID SILICA SOL EITHER BY CONVERTING A PORTION OF THE ALUMINA TO A WATER SOLUBLE STATE OR BY COATING THE ALUMINA WITH A WATER SOLUBLE ALUMINUM COMPOUND, SAID ACTIVATING AGENT BEING SELECTED FROM THE GROUP CONSISTING OF ACETIC ACID, FORMIC ACID, ALUMINIUM ISOPROPOXIDE, CHLOROHYDROL AND TETRAMETHYLAMMONIUM HYDROXIDE. 